• Korean Journal of Mathematics
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• 제30권2호
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• pp.315-333
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• 2022

We give a general procedure to analyze the structure for certain ℂ-Fuchsian subgroups of some non-arithmetic lattices. We also show their presentations and describe their fundamental domains which lie in a complex geodesic, a set homeomorphic to the unit disk.

• 대한수학회보
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• 제51권5호
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• pp.1375-1397
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• 2014

In this paper we establish codimension reduction theorem for submanifolds of a (4m+3)-dimensional unit sphere $S^{4m+3}$ with Sasakian 3-structure and apply it to submanifolds of a quaternionic projective space.

• 한국수학교육학회지시리즈A:수학교육
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• 제22권2호
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• pp.5-12
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• 1984

mod pin Steenrod algebra $A_{p}$ 는 steenrod reduced powers p$^n$ 및 Bockstein coboundary operation $\beta$에서 algebra로서 생성되었다. 그들 사이의 관계도 알려져 있다. 이 논문에서는 iterated loop space의 $A_{p}$ -module structure를 결정하는 한 명제인 (equation omitted)를 증명했다.

• 한국통신학회논문지
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• 제21권1호
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• pp.251-268
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• 1996

In this paper, a higher-order feedforward neural network called ridge polynomial network (RPN) which shows good approximation capability for nonlnear continuous functions defined on compact subsets in multi-dimensional Euclidean spaces, is presented. This network provides more efficient and regular structure as compared to ordinary higher-order feedforward networks based on Gabor-Kolmogrov polynomial expansions, while maintating their fast learning property. the ridge polynomial network is a generalization of the pi-sigma network (PSN) and uses a specialform of ridge polynomials. It is shown that any multivariate polynomial can be exactly represented in this form, and thus realized by a RPN. The approximation capability of the RPNs for arbitrary continuous functions is shown by this representation theorem and the classical weierstrass polynomial approximation theorem. The RPN provides a natural mechanism for incremental function approximation based on learning algorithm of the PSN. Simulation results on several applications such as multivariate function approximation and pattern classification assert nonlinear approximation capability of the RPN.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1997년도 한국자동제어학술회의논문집; 한국전력공사 서울연수원; 17-18 Oct. 1997
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• pp.422-425
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• 1997

We consider the robust control problem for nonminimum phase(NMP) systems with parametric uncertainty which appear often in aircraft and missile control. First, a new method that makes such an uncertain NMP system to be factored as a interval minimum phase(MP) transfer function and a time delay term in the Pade approximation form has been presented. The controller to be proposed consists of a compensator $C_{Q}$(s) with Smith predictor in the internal model control(IMC) structure, so that it can have good robustness and performance against the structured uncertainty and the time delay behaviour due to NMP plant the $C_{Q}$(s) is designed on the MP model by using QFT. The stability and performance of overall system has been evaluated by the generalized Kharitonov theorem.rem.

• 한국융합학회논문지
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• 제4권4호
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• pp.41-48
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• 2013

Observer design for system with unknown input was carried out. First, Kalman filter was considered to estimate system state with White noise. With the results of Kalman filter design, state observer, controller properties, including controllability and observability, and the Kalman filter structure and algorithm were also studied. Kalman filter algorithm was applied to Position and velocity measurement based on Kalman filter with white noise, and it was constructed and achieved by programming based on Matlab programming. Finally, observer for system with unknown input was constructed with the help of Gershgorin's disc theorem. With the designed observer, system states was constructed and applied to system with unknown input. By simulation results, estimation performance was verified. In this project, state feedback control theory, observer theory and relevant design procedure, as well as Kalman filter design were understood and used in practical application.

• ETRI Journal
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• 제24권5호
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• pp.381-390
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• 2002

We analyze the performance of a telecommunications management network (TMN) system using models of networks of queues, Jackson's theorem, and simulation. TMN systems for managing public asynchronous transfer mode (ATM) networks generally have a four-level hierarchical structure consisting of a network management system, a few element management systems (EMSs), and several pairs of agents and ATM switches. We construct a Jackson's queuing network and present formulae to calculate its performance measures: distributions of queue lengths and waiting times, mean message response time, and maximum throughput. We perform a numerical analysis and a simulation analysis and compare the results.

• 대한수학회지
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• 제47권5호
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• pp.1001-1015
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• 2010

Let M be a $C^{\infty}$ real hypersurface in $\mathbb{C}^{n+1}$, $n\;{\geq}\;1$, locally given as the zero locus of a $C^{\infty}$ real valued function r that is defined on a neighborhood of the reference point $P\;{\in}\;M$. For each k = 1,..., n we present a necessary and sufficient condition for there to exist a complex manifold of dimension k through P that is contained in M, assuming the Levi form has rank n - k at P. The problem is to find an integral manifold of the real 1-form $i{\partial}r$ on M whose tangent bundle is invariant under the complex structure tensor J. We present generalized versions of the Frobenius theorem and make use of them to prove the existence of complex submanifolds.

• 천문학회보
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• 제37권2호
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• pp.127.2-127.2
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• 2012

Space weather prediction related to flares and CMEs is an important issue these days. It is, however, hard to estimate magnetic energy of invisible coronal magnetic structure. The virial theorem is one of the ways to determine the magnetic energy. In this study, we performed a series of MHD simulation of an emerging flux tube and apply the virial theorem to the simulation results and derive energetics of coronal structures. We then analyze real observational data on NOAA 11302 to derive the distributions of physical quantities, such as density, temperature, velocity and magnetic field. We also use knowledge form simulation analysis to estimate the magnetic energy of NOAA 11302.

• Advances in aircraft and spacecraft science
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• 제10권2호
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• pp.159-177
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• 2023

In this paper we proposed the aerodynamic numerical analysis with linear matrix inequality theorem of intelligent control, which is believed to be applicable in the application not only a function of the block size and reduced wind speed but itself depends on both the size and the aspect ratio of the structure, not on the total scruton number. In order to improve the accuracy of the results, the optimization curve was optimized for the test to evaluate the response in the time of achieving the results and we focus on the results that found a significant influence from the assumptions used for damage propagation for aircraft structural analysis of composite materials. Finally, the numerical simulations confirmed the effectiveness of the method.